import re
from urllib.parse import urljoin
from bs4 import BeautifulSoup

class HtmlParser:

    def parser(self,page_url,html_cont):
        '''
        解析网页
        :param page_url:
        :param html_cont:
        :return:返回url和数据
        '''
        if page_url is None or html_cont is None:
            return
        soup = BeautifulSoup(html_cont,'html.parser',from_encoding='utf-8')
        new_url = self._get_new_urls(page_url,soup)
        new_data = self._get_new_data(page_url,soup)
        return new_url,new_data


    def _get_new_urls(self,page_url,soup):
        '''
        获取新的url集合
        parm
        :return: 返回新的url集合
        '''
        new_urls = set()
        links = soup.find_all('a',href = re.compile(r'/item/[%\w]+'))
        for link in links:
            new_url = link['href']
            new_full_url = urljoin(page_url,new_url)
            new_urls.add(new_full_url)
        return new_urls


    def _get_new_data(self,page_url,soup):
        '''
        抽取有效数据
        :param page_url:
        :param soup:
        :return:
        '''
        data = {}
        data['url'] = page_url
        title = soup.find('dd',class_='lemmaWgt-lemmaTitle-title').find('h1')
        data['title'] = title.get_text()
        summary = soup.find('div',class_='lemma-summary')
        data['summary'] = summary.get_text()
        return data